Seizure Induced by Defecation in a 15-Year Old Autistic Patient: A Case Report and Literature Review

Epilepsy in autism is a relatively common phenomenon. However, reflex seizures provoked by multifactorial stimuli are rare in these patients. We here reported the first case of defecation-induced seizure in a 15-year old autistic girl. The patient had been diagnosed with epilepsy within the first year after birth; however, seizures induced by bowel movements were observed at the age of 15. Reflex seizures showed a myoclonic pattern represented with one-sided neck deflection. EEG showed an abnormal polyspike and wave pattern during defecation while the patterns were normal between the attacks. The patient was partially responsive to adrenocorticotropic hormone therapy with a reduced frequency of both reflexes and generalized seizures. Phenobarbital therapy was effective to manage recurrent seizure attacks. Although seizure is commonly encountered in autism, reflex seizures induced by defecation have not been previously reported in this condition.


Introduction
Iran J Child Neurol. Summer 2020 Vol. 14 No. 3 reflex seizures (6)(7)(8). Although neurological and gastrointestinal systems are interrelated (9), reflex seizures triggered by digestive stimuli are relatively infrequent. In particular, reflex seizure following defecation represents an extremely rare phenomenon with only two reports of reflex seizures linked to defecation (10,11).
Autism is a multifactorial mental condition characterized by abnormalities in social communications (12). Epilepsy is associated with a relatively common adverse outcome in autism.
The concurrent epileptic phenotype in autistic patients may further weaken communication skills and reduce life expectancy (13). Although seizures are common in autistic patients with a frequency of 5-38% (12,14), reflex seizures are rare in autism.
Here, we reported the first case of reflex seizure provoked by defecation in a teenager with autism.

Discussion
This was the first report of a 15-year old autistic girl presenting with defecation-induced myoclonic reflex seizures. The defecation-induced reflex seizure is an extremely rare phenomenon previously reported in only two cases (10, 11). The first case was a 5-year-old girl (11), and the second was a 9-year-old boy (10). Similar to our patient, reflex seizures were followed by juvenile myoclonic epilepsy in both cases (10,11). At the intervals between seizure attacks, no EEG abnormality was detected; however, an abnormal polyspike wave in the left frontotemporal region was observed in the EEG pattern during seizures. This was also similar to the EEG pattern observed in the previously reported cases (10,11).
In a previous case of seizure provoked by defecation, the attacks occasionally occurred within 1-2 min following bowel movement but not during the activity (10)., which is not consistent with our case, as the seizures were initiated during defecation. In their reports, Harbord et al. seizure. In the present case, ACTH therapy relieved the seizure attacks. After seizure recurrence ten days after hospitalization, phenobarbital was effective to reduce the attacks. However, the seizure attacks were refractory to common antiepileptic treatments. A partial response to common anti-epileptic drugs in our case was probably due to the autism in our case, which is known to be associated with drug-refractory seizures (15).
It seems that the intestinal movements can stimulate the temporal region of the brain, which subsequently leads to seizure attacks. It has been also reported that the supplementary motor area (SAM) receives neurological signals provoked by sphincter activity during a bowel movement (16). In parallel, the contraction of the particular muscles, including sphincter in the pelvis has been noted to activate the SAM region (17). These suggest that the contraction of such muscles may be the potential stimulators of reflex seizures during defecation. More studies are needed to explore the neurological pathways connecting defecation to seizure and epilepsy.
Autism is commonly associated with epilepsy (14). Autism and epilepsy share two common pathological features; 1-diminished inhibitory cycles of minicolumn, and 2-reduced inhibitory effects of gamma-aminobutyric acid (GABA).
These effects are known to predispose the brain to stimulatory factors, which subsequently leads to seizures due to the higher ratio of stimulatoryto inhibitory signals within the cortex (14).
Besides, the development of epilepsy and seizure in autism may also be related to nutritional factors (18). Furthermore, a role has been proposed for inflammation as a triggering factor of epilepsy in autism (19). In our patient, however, inflammatory markers, including CRP and ESR were within normal ranges at admission and did not change in the course of the disease. The potential contributors intercalating autism and seizure are yet to be identified.

In Conclusion
Reflex seizure induced by defecation is a rare clinical condition. In autistic patients, defecationprovoked reflex seizures can present with partial refractory epilepsy requiring multiple therapeutic Iran J Child Neurol. Summer 2020 Vol. 14 No. 3 strategies. Regarding a high prevalence of various types of seizures in autism, it is recommended to carefully monitor these patients for identifying possible triggering factors for the seizure attacks.

Acknowledgment
Thanks to the patient's parents. Informed consent was acquired from them.

Conflict of interests:
None to declare.